The Catalinbread Formula No. 55 is an overdrive pedal from Portland, Oregon maker Catalinbread, built to put the character of a Fender 5E3 Tweed Deluxe amp on a pedalboard. Guitar.com describes it as "a JFET-based overdrive designed to replicate those classic Tweed Deluxe flavours"12. Where most overdrives clip the signal with op-amps or diodes, this one uses JFET transistors, the same family of parts Catalinbread used in the earlier Formula No. 5, to behave more like the input stages of a tube amp.
Catalinbread presented the pedal as a "next-generation 5E3 Tweed Deluxe inspired overdrive with incredible range, from Grant Green to Crazy Horse!"2, meaning it spans clean, jazzy warmth through to ragged, cranked-amp grind. It was announced at the winter NAMM show and went on sale at the end of January 20173.
A JFET overdrive voiced after the 5E3 Tweed Deluxe
The 5E3 Tweed Deluxe is the mid-1950s Fender circuit players associate with touch-sensitive breakup: turn it up and it goes from clean to gritty with a wide, loose low end. The Formula No. 55 is Catalinbread's pedal-format take on that behavior. The JFET topology matters here because JFETs clip more like a tube gain stage than like the diode clipping in a typical overdrive, which is the approach Catalinbread carried over from the original Formula No. 5, a circuit that used 2N5457 JFETs4.
The pedal sits in the same amp-in-a-box territory as Catalinbread's other Foundation Overdrive pedals, which model specific vintage amps rather than generic overdrive curves3.
Controls
The Formula No. 55 keeps the control set small, in keeping with the single-knob ethos of the tweed amps it copies3:
| Control | What it does |
|---|---|
| Master | Sets the overall output level, independent of how hard the "amp" is being pushed |
| Presence | Shapes the high-frequency response, like a tweed amp's presence control |
| Tone | A single-knob tone control, modeled after the one-knob tone circuits of old Fender amps such as the Harvard 5F105 |
| Volume | Sets the drive level, like turning up a Tweed Deluxe |
The Master control is the practical difference between this pedal and the real amp: on a 5E3, volume and drive are the same knob, so the amp only breaks up when it is loud. Here, Volume sets the breakup and Master sets how loud that breakup reaches the room3.
Part of the Foundation Overdrive series
The Formula No. 55 belongs to Catalinbread's Foundation Overdrive range, a series of drive pedals that each recreate a specific classic amp32. It is the successor to the Formula No. 5, which itself went through two versions: the original, and a 2011 update that Aion FX documents as different enough that it reproduced both as separate projects46. The Formula No. 5 used 2N5457 JFETs, a part Aion FX notes is no longer available in through-hole format4.
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Questions
What amp is the Catalinbread Formula No. 55 based on?
It is voiced after the Fender 5E3 Tweed Deluxe. Catalinbread described it as a next-generation 5E3-inspired overdrive, and the circuit is JFET-based rather than op-amp-based12.
Does the Formula No. 55 have a master volume?
Yes. The layout is Master, Presence, Tone and Volume, so you can set the drive level with Volume and the output level separately with Master3.
How much does the Catalinbread Formula No. 55 cost?
Guitar.com listed it at $189 USD in January 20261.
Sources (6)
- Lazy J x ThorpyFX The J review: a superb tweed amp emulation, Guitar.com, 2026-01-14
- Catalinbread Formula No. 55 Overdrive, Delicious Audio, 2017-02-08
- NAMM 2017: Catalinbread Formula No. 55 Overdrive pedal offers some heavy tweed, gearnews.com, 2017-01-18
- Asteria Preamp Drive Mk. I, Aion FX, 2020-11-23
- Formula No. 5 (Spaceship Art), Catalinbread Effects
- Asteria Preamp Drive Mk. II, Aion FX, 2020-11-23
